So, I’m desperate now, and I need to reach out for help. I have tried over 10 hours to make sense out of some of these things, but with no success.
First question is, is it normal that the impulse response moves without you moving the mic or touching anything. I don’t understand the point of trying to move your speakers 1 mm or whatever it is when every time you redo the measurement, it extends or changes. I have always used distance lasers to get my speakers accurate because I find it considerably more reliable with repeatable results. I use a umik-1 mic.
I would assume that you don’t need to do super long sweeps to make use of the timing reference for an impulse response, correct?
I have a bunch more questions, but I’ll just start off simple.
Are you ticking adjust clock with acoustic reference option? USB mics have timing issues and especially longer sweeps will deviate without it. Even when ticked, some variation from measueemt to measurement is possible but should be less than 1mm. You can use the new 64k sweeps for best timing precision.
That’s a variation of about 2 microseconds between measurements which is less than a millimeter. This is normal and actually a great achievement by John given the clock deviations caused by the USB mic interface. The only way to remove even that kind of deviation is to use an analogue measurement mic with a microphone amp.
Yes. I usually need to add like 6dB headroom myself although I don’t hear any difference, Roon has a very sensitive clipping detector. But if you are hearing something strange, it could be ringing. You may need to check your applied method for the creation of filters. Send me your mdat and I can have a look.
The distortion I’m hearing happens on bass notes, and Roon needs at least 6db of headroom before i cant really hear it anymore…and 10db of headroom before roons clipping indicator stops showing clipping.
Your speakers have an 8th order crossover @ 1800Hz. When the phase shift this XO causes is corrected, tweeter and woofer signal arrives at the LP at the same time and the sound stage forms at the level of the higher driver.
Your mdat and rePhase settings to create the xo phase shifter are all in this zip:
By the way, 0.7 slope is perfect for 75dB volume level. If you think bass is not enough, just turn up the volume. We hear bass frequencies louder than the others when volume increases. I’d only increase 0.7 if I listen regularly at low levels (which I have to do at nights unfortunately!)
I am pretty certain a different dac would not change your REW measurements or filters. The microphones are far less sensitive than any difference a DAC will make. The lowpass filter slope rolloffs you mention are probably happening way beyond 24kHz in the upsampled versions. If you’ve bat ears, you might hear some tonality difference in the very high frequencies but the filters I made for you do not change anything beyond 500Hz anyway so no worries there.